Head interconnect circuit with alignment finger

ABSTRACT

A head interconnect circuit for connecting transducer elements of a data head to drive circuitry including an alignment finger on a lead tip for aligning leads relative to connectors or solder pads for electrically connecting heads to drive circuitry. A method for connecting a head interconnect circuit to a printed circuit supported on an head actuator including aligning an alignment finger on the lead tip with a printed surface of a drive circuit for soldering leads on the lead tip to solder pads or connectors on the drive circuit.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to Provisional ApplicationSerial No. 60/100,246 filed Sep. 14, 1998, and entitled “HEAD GIMBALASSEMBLY INTERCONNECT ALIGNMENT”.

FIELD OF THE INVENTION

The present invention relates to a data storage device. In particular,the present invention relates to a head interconnect circuit forelectrically connecting transducer elements of a data storage device toprocess circuitry for read or write operations.

BACKGROUND OF THE INVENTION

Disc drive systems are well known which include data heads includingtransducer elements for reading or writing data to a recordable disc.Transducer elements of the data heads are electrically connected todrive circuitry through a head interconnect circuit. Conductive paths onthe head interconnect circuit electrically connect head leads connectedto transducer elements on the head to circuit leads connected to drivecircuitry.

Heads are supported relative to a disc surface by a head actuator orE-block. A drive circuit is mounted on the head actuator and circuitleads on the head interconnect circuit are connected to lead connectorsor solder pads on the drive circuit. Leads are supported along an edgeof a lead tip of the head interconnect circuit and connectors or solderpads are aligned along a slot or edge of the drive circuit. The lead tipis inserted into the slot or aligned with the edge to connect circuitleads to connectors. Leads are soldered to connectors to electricallyconnect transducer elements of the head to drive circuitry.

Prior to soldering, leads are aligned with the connectors or solder padsto assure desired electrical connection for read and write operations.Drive circuits mounted on a head actuator or E-block include aconductive metal substrate supporting a printed circuit. Duringsoldering operation, solder can spill from the solder pad or connector.Solder spill to a conductive metal substrate can short the electricalconnection between the data heads and drive circuitry so that the dataheads are defective. The present invention addresses these and otherproblems, and offers other advantages over the prior art.

SUMMARY OF THE INVENTION

A head interconnect circuit for connecting transducer elements of a datahead to drive circuitry including an alignment finger for aligning leadsrelative to lead connectors or solder pads for electrically connectingheads to drive circuitry.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective illustration of a disc drive.

FIG. 2 is a perspective illustration of an actuator block supportingheads for read or write operations.

FIG. 3 is a perspective illustration of a head interconnect circuit.

FIG. 4 is a detailed perspective illustration of a lead tip of a headinterconnect circuit and solder pads on a drive circuit.

FIG. 5 is a cross-sectional view of leads from multiple headinterconnect circuits soldered to solder pads of a drive circuit asgenerally taken along line 5,6—5,6 of FIG. 4.

FIG. 6 is an alternate cross-sectional view of leads from multiple headinterconnect circuits soldered to solder pads of a drive circuit asgenerally taken along lines 5,6—5,6 of FIG. 4.

FIG. 7 is a perspective illustration of an embodiment of a lead tip of ahead interconnect circuit of the present invention including analignment finger.

FIG. 8 is a schematic illustration of the alignment finger of FIG. 7having an alignment edge aligned with a printed surface of a drivecircuit.

FIG. 9 is a plan view of a lead tip of an embodiment of a headinterconnect circuit of the present invention connected to a testconnector board prior to assembly in a disc drive.

FIG. 10 is an operation flow chart for connection of leads to drivecircuitry.

The drawings are for illustration and the features illustrated thereinare not necessarily drawn to scale.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a rotary disc drive 50 including a disc chassis 52,discs 54 and a head actuator or E-block 56. Discs 54 are rotationallycoupled to chassis 52 via a disc spindle drive 58 (illustrateddiagrammatically) for rotation, as illustrated by arrow 59. Discs storedata on concentric data tracks. The head actuator 56 supports data heads60 relative to a disc surface. In FIG. 1, head actuator 56 is rotatedvia operation of voice coil motor (VCM) 62 to move heads 60 along anarcuate path as illustrated by arrow 64 to position heads 60 relative toselected data tracks for read or write operations.

FIG. 2 is a perspective illustration of an embodiment of a head actuator56 supporting heads 60. As shown in FIG. 2, head actuator 56 includes astem 66, a motor coil 68 and a plurality of stacked actuator arms 70. Abearing 72 or other pivot connection rotationally connect actuator 56 tochassis 52. Bearing 72 extends through a bearing channel 74 in the stem66 to rotationally connect actuator 56 to rotationally support heads 60for placement relative to selected data tracks. Motor coil 68 issupported for operation in a backiron assembly 78 (illustrated inFIG. 1) to form the VCM 62 for moving head actuator 56 along path 64 forhead placement relative to selected data tracks.

Flexible suspension assemblies 80 are coupled to and extend from theactuator arms 70 to support a plurality of heads 60 relative to the discsurface. The suspension assemblies 80 illustrated in FIG. 2 include aload beam 82 and a gimbal spring 84. The load beam 82 and gimbal spring84 flexibly support heads 60 relative to the disc surface to follow thetopography of the disc surface. Heads 60 include transducer elements forread or write operations. Transducer elements can be inductive typetransducer elements, magneto-resistive and magneto-optical transducerelements. Transducer elements are electrically connected to a drivecircuit 86 connected to head actuator 56 via a head interconnect circuit88.

FIG. 3 is a detailed illustration of an embodiment of a headinterconnect circuit 88. The embodiment shown includes base 90 having abody portion 92, and a tail 94; a plurality of head leads 96 and circuitleads 98. Head leads 96 are formed at an end of body portion 92 toelectrically connect to transducer elements supported on slider 100.Tail 94 extends from body portion 92 to a lead tip 104 supportingcircuit leads 98. A portion of the tail 94 extends along an actuator arm70 to position lead tip 104 proximate to the drive circuit 86(illustrated schematically in FIG. 3). Conductive paths 108 on base 90electrically connect head leads 96 to the circuit leads 98 forconnecting transducer elements to drive circuit 86 for read/writeoperations. Base 90 is typically formed of a flexible polyimide materialand the conductive paths 108 are formed of copper traces. The number ofleads 96, 98 and paths 108 depends upon the number of electricalconnections required for the transducer elements supported by the slider100.

As shown in FIG. 4, drive circuit 86 includes series of solder pads orconnectors 110-1, 110-2, 110-3, 110-4 extending along a length of aninterconnect slot 112 for connecting circuit leads 98-1, 98-2, 98-3,98-4 to drive circuitry. In the embodiment shown, upper and lower leadpads 110-1, 110-2, 110-3, 110-4 are aligned along upper and lower slotedges 112-1, 112-2 to connect circuit leads 98-1, 98-2, 98-3, 98-4 forupper and lower head interconnect circuits 88-1, 88-2 as shown in FIG. 5to electrically connect heads supported by upper and lower suspensionassemblies 80 connected to an actuator arm 70.

Circuit leads 98 extend along a lead edge 114 of lead tip 104 as shownin FIG. 4 and are spaced from end 116 to align each circuit lead 98-1,98-2, 98-3, 98-4 with a solder pad or connector 110-1, 110-2, 110-3,110-4. In the embodiment illustrated in FIGS. 4-5, lead tip 104 isinserted into slot 112 so that an end 116 of the lead tip 104 abuts anend 118 of slot 112. Leads 98 are sequentially spaced along edge surface114 from end 116 to align with pads 110-1, 110-2, 110-3, 110-4 when end116 abuts end 118 of drive circuit 98. As shown, in FIGS. 4-5, leads 98are bent and soldered to pads 110. Alternatively pads 110-1, 110-2,110-3, 110-4 can be spaced along an exposed edge surface (not shown) forconnection of leads to drive circuitry.

As comparatively shown in FIGS. 5-6, the elevation of edge 114 relativeto a printed surface 120 (reference surface) of circuit 86 affectsplacement of leads 98 relative to pads 110. As shown in FIG. 5, edge 114is flush with printed surface 120 and in FIG. 6, edge 114 isout-of-alignment with or lower than printed surface 120. Alternatively,edge 114 can be raised relative to the printed surface 120. During thesoldering process, solder can spill from the solder pads 110 asillustrated diagrammatically in FIG. 6. The drive circuit 86 shown inFIGS. 5-6 is a rigid printed circuit board formed of a metal plate 122,such as Aluminum or stainless steel, and an insulating layer 124 such aspolyimide. Although a particular circuit board construction isdescribed, the circuit board is not limited to the specific constructionor materials described. Circuit paths 108 and solder pads 110 are formedon insulating layer 124. Depending upon the alignment of edge 114 withprinted surface 120 solder spill can interfere with and potentiallyshort the electrical connection between the head and drive circuitry.

In particular, as shown in FIG. 6, when edge 114 is lower than printedsurface 120, solder spill 126 can contact the metal plate 122 of thecircuit board shorting the head so that the head is defective. Thepresent invention relates to a head interconnect circuit 130 with analignment feature for aligning lead edge 114 relative to the printedsurface 120 or connector of drive circuit 86. An embodiment of the headinterconnect circuit 130 is illustrated in FIGS. 7-9 where like numbersare used to identify like parts of head interconnect circuit 88.

In the embodiment shown, the alignment feature includes an alignmentfinger 132 on lead tip 134 having an alignment edge 136 for aligninglead edge 114 with printed surface 120 or connectors 110. In theembodiment shown, alignment edge 136 is co-planar with and aligned withedge 114 on lead tip 134. As shown in FIGS. 7-8, the alignment finger132 is inserted into the slot 112 to align the edge 136 with the printedsurface 120 or reference surface of the drive circuit 86. Alignment ofedge 136 with reference surface aligns edge 114 with printed surface 120and solder pads 110 to reduce solder spill to metal plate 122.Alternatively, alignment edge of alignment finger 132 can be located toalign with a parallel back surface 138 to align edge 114 with printedsurface 120 or connectors 110. Engagement of the finger 132 with backsurface 138 can secure the lead tip 134 in place and prevent the leadtip 134 from “popping out”.

FIG. 9 is a detailed illustration of lead tip 134. As shown, lead tip134 is formed integral with a test connector board 140. Connector board140 is used to test electrical connection of the heads prior to assemblyin a disc drive. For assembly, connector board 140 is separated fromlead tip 134 as illustrated by line 142 and tab 144 is separated fromsoldered leads 98. As shown separation of connector board 140 at line142 forms finger 132. In the embodiment shown, lead tip 134 includes ashoulder 146 and a shoulder flap 148. For assembly shoulder flap 148 isfolded behind shoulder 146 and inserted into a slot (not shown) onactuator block 56 to secure lead tips for assembly to drive circuit 86.

FIG. 10 is a flow chart for assembly. As shown for assembly, a lead edge114 is aligned with a connector edge 112-1, 112-2 of a printed or drivecircuit as illustrated by block 150. Alignment finger 132 is used toalign lead edge 114 with a printed surface 120 of the drive circuit 86as illustrated by block 152 and leads 98 are soldered to connectors orsolder pads 110 as illustrated by block 154.

A head interconnect circuit 130 for connecting transducer elements of adata head 60 to drive circuitry including a lead tip 104 having aplurality of leads 98 aligned along a lead edge 114 and an alignmentfinger 132 for aligning leads 98 relative to connectors or solder pads110 for connection to drive circuitry.

It is to be understood that even though numerous characteristics andadvantages of various embodiments of the present invention have been setforth in the foregoing description, together with details of thestructure and function of various embodiments of the invention, thisdisclosure is illustrative only, and changes may be made in detail,especially in matters of structure and arrangement of parts within theprinciples of the present invention to the full extent indicated by thebroad general meaning of the terms in which the appended claims areexpressed. For example, the particular elements may vary depending onthe particular application while maintaining substantially the samefunctionality without departing from the scope and spirit of the presentinvention. In addition, although the preferred embodiment describedherein is directed to a magnetic disc drive system, it will beappreciated by those skilled in the art that the teachings of thepresent invention can be applied to other systems, like an optical datastorage system, without departing from the scope and spirit of thepresent invention.

What is claimed is:
 1. A head interconnect circuit for connectingtransducer elements of a data head to an interfacing circuit of a discdrive comprising: an insulated base portion having a base surface andfirst and second edge surfaces intersecting with the base surface; aplurality of head leads; a plurality of circuit leads on the basesurface of the base portion sequentially spaced from the first edgesurface; a plurality of conductive paths electrically connecting thehead leads and the circuit leads; and an alignment finger having afinger portion extending from the base portion and the finger portionincluding a third edge surface intersecting the first edge surface toform interfacing surfaces, the first edge surface on the base portionbeing positionable to align the circuit leads relative to interfacingterminals on the interfacing circuit and the third edge surface of thefinger portion being positionable to align the second edge surface ofthe base portion relative to the interfacing circuit.
 2. The headinterconnect circuit of claim 1 wherein the base portion is sized forinsertion into a slot of the interfacing circuit of the disc drivehaving solder pads aligned therealong forming the interfacing terminals.3. The head interconnect circuit of claim 1 wherein the base portion isformed of a flexible material.
 4. The head interconnect circuit of claim1 wherein the base portion is formed of a polyimide material.
 5. Thehead interconnect circuit of claim 1 wherein the conductive paths areformed of copper traces on the base portion.
 6. The head interconnectcircuit of claim 1 wherein the base portion includes a body portion andthe body portion is sized to be mounted on a flexible suspensionassembly of a head actuator.
 7. The head interconnect circuit of claim 1wherein the alignment finger is generally rectangular shaped.
 8. Thehead interconnect circuit of claim 1 wherein the third edge surface onthe finger portion of the finger and the first edge surface of the baseportion are generally perpendicular.
 9. The head interconnect circuit ofclaim 1 wherein the third edge surface on the finger portion and thesecond edge surface of the base portion are generally parallel.
 10. Thehead interconnect circuit of claim 1 wherein the base portion includes abody portion and a tail portion.
 11. The head interconnect circuit ofclaim 1 wherein the head leads, the circuit leads and the conductivepaths are printed on the base surface.
 12. A head interconnect circuitfor connecting transducer elements of a data head to drive circuitrycomprising: a base portion including a plurality of leads on a basesurface of the base portion to connect the transducer elements to thedrive circuitry; means for aligning the base portion of the headinterconnect circuit relative to an interface circuit having interfaceterminals thereon for connecting the leads to the drive circuitry. 13.The head interconnect circuit of claim 12 wherein the interface circuitof the drive circuitry includes a conductive substrate and the means foraligning includes a finger having an alignment edge to align an edgesurface of the base portion relative to a printed surface of theinterface circuit to limit solder flow to the conductive substrate ofthe interface circuit.
 14. The head interconnect circuit of claim 12wherein the means for aligning includes a finger including an alignmentedge for positioning an edge surface of the base portion intersectingthe base surface of the base portion relative to a printed surface ofthe interface circuit having the interface terminals thereon.
 15. Thehead interconnect circuit of claim 12 and the means for aligningcomprises an edge surface on the base portion for aligning the leads onthe base portion with the interface terminals spaced along the interfacecircuit.
 16. In combination: an interface circuit including a pluralityof terminals spaced along a surface of the interface circuit; and a headinterconnect circuit including an insulated base portion having aplurality of head leads, a plurality of circuit leads, and a pluralityof conductive paths on a base surface of the base portion, the pluralityof conductive paths electrically connecting the plurality of head leadsand the plurality of circuit leads and the interconnect circuitincluding an alignment finger extending from the base portion includinga first edge surface intersecting a second edge surface of the baseportion having the plurality of circuit leads sequentially spacedtherefrom and the first edge surface of the finger is longitudinallyaligned with a third edge surface of the base portion to align the thirdedge surface with the surface of the interface circuit having theplurality of terminals thereon.
 17. The combination of claim 16 whereinthe interface circuit includes a slot having an end surface and theplurality of terminals are sequentially spaced from the end surface andthe interconnect circuit is inserted into the slot and the second edgesurface of the interconnect circuit is aligned with the end surface ofthe interface circuit to align the plurality of leads on the headinterconnect circuit with the plurality of terminals on the interfacecircuit.
 18. The combination of claim 17 wherein the first edge surfaceof the finger abuts the surface of the interface circuit to align thethird edge surface of the base portion with the interface circuit. 19.The combination of claim 18 wherein the interface circuit includes aconductive substrate portion and an insulating portion having theplurality of terminals thereon and the first edge surface of thealignment finger aligns the third edge surface of the interconnectcircuit with the insulating portion of the interface circuit.